President Obama’s plan to end the government’s mass collection of Americans’ phone records got mixed reviews when unveiled last week. But even whistleblower Edward Snowden, whose data-leaking sparked the changes, called the proposal a good start.

Said Snowden: “This is a turning point, and it marks the beginning of a new effort to reclaim our rights from the NSA and restore the public’s seat at the table of government.”

The sentiment was echoed by other critics of the National Security Agency’s widespread and indiscriminate bulk collection of phone records. Said Anthony Romero, executive director of the American Civil Liberties Union: “The president’s plan is a major step in the right direction and a victory for privacy.”

Yet Romero and others rightly caution that this should be the beginning of surveillance reform, not the end.

Under the plan, the NSA would end its bulk collection of telephone records. Phone companies would hold onto data (which doesn’t include the content of calls) for 18 months. The government would need prior approval from the Foreign Intelligence Surveillance Act (FISA) court to search those records, though the plan does include an exemption for unspecified “emergency” situations. The plan requires prior approval for the NSA to even query phone companies about their customers’ records.

Unfortunately, members of Congress introduced a bill that does not include this stricter judicial review. The bipartisan House proposal would allow the FBI and other agencies to directly demand information from phone companies. The ACLU’s Michelle Richardson said, “It’s not a fix. It’s not even a half-measure.”

She is right.

Obama’s plan also raises concerns. It doesn’t address other controversial surveillance programs and actions by the NSA including hacking into encryption systems and collections of financial records, Internet information and email data. The plan also lacks detail about the standards needed to get a FISA court order or about what constitutes emergencies to bypass the courts.

As the administration and Congress fashion an effective plan, those questions must be answered. And Congress should resist pushing competing plans that make the process less transparent and less protective of privacy rights.

Preserving Americans’ privacy rights and protecting Americans against terrorist threats do not have to be in conflict. Intelligence agencies need the ability to seek and get information that could make the U.S. safer from such threats. Effective oversight of those agencies’ activities should not hamper that.

The NSA’s indiscriminate eavesdropping went too far. An expert panel Obama tapped to review the program said earlier this year that such mass collections weren’t even essential in preventing terror attacks.

Obama said the plan was needed to win back the trust of U.S. citizens. He’s right. But this plan is just the start.